The present invention relates to a grating, and more particularly to one having tubular elements.
Conventional gratings can generally be categorized into three types:
(1) Shy types: As shown in FIGS. 1A and 1B, such gratings are consituted by metal wires 101 or metal strips 102. Such gratings have a high impact strength but a low rigidity and are weak in themselves. In addition, they are coarse in appearance.
(2) Extruded types: As shown in FIG. 2, such grating includes extruded slit ribs 201 and connectors 202 of aluminum so that they form rhombic meshes 203 when a tensile force is transversely applied thereto. Such grating can be easily produced but have a low impact strength, easily rupture at connectors 202 upon impact, and are weak in themselves.
(3) Tubular types: Such gratings can be further divided into two sub-types:
(A) As shown in FIGS. 3 and 5, the first sub-type of grating includes a vertical tube 301, a horizontal tube 302, an angle piece 304, a screw 303 attaching angle piece 304 to tube 301, and a screw 305 attaching angle piece 309 to tube 302.
(B) As shown in FIGS. 4 and 5, the second sub-type of grating includes a first vertical half 401, a second vertical half 402 cooperating with first half 401 to form a tubular element a horizontal tube 403, and two screws screwing attaching horizontal tube 403 to second vertical half 403 through holes 405 in second half 402.
Although the above two sub-types of gratings have a beautiful appearance and good rigidity, they are material-consuming and complicated to manufacture and assemble.